New Delhi: An X1.8 solar flare erupted from a cluster of sunspots designated as active region (AR) 3872, by the US National Oceanic and Atmospheric Administration (NOAA). The active region has a complex magnetic configuration and is sandwiched between two other clusters of sunspots, designated as AR 3873 and AR 3869. The solar flare was associated with a fast and narrow coronal mass ejection (CME), energetic outbursts where hot gas from the atmosphere of the Sun is violently launched outwards into space, carrying with it a portion of the tangled magnetic fields of the Sun. Most of the material will miss the Earth, but a glancing blow is expected to the Earth on 28 October.
The CME observed on 26 October, associated with the X1.8 solar flare. (Image Credit: NASA/SDO/SIDC).
The plasma from the Sun is travelling between 1,500 and 1,600 kilometres per second, which is more than twice the average speeds of coronal mass ejections. The Space Weather Prediction Centre (SWPC) analysis also indicates that a glancing blow from the CME may strike the Earth on 28 October. According to the SWPC forecast, a negative polarity coronal hole high speed stream (CH HSS) may become geoeffective around 28 October as well. These are more steady, gentle streams of solar particles directed at the Earth, as against the unpredictable and chaotic CMEs. The CH HSS and the glancing blow from the CME can together cause geomagnetic disturbances.
Space Weather Forecast
According to the UK Met Office, “Activity is expected to be Quiet to Active (Kp 2-4) during Days 1-2 (27-28 Oct) with a chance of peak G1/Minor to G2/Moderate Storm (Kp 5-6) conditions during Days 1 and 2 (27-28 Oct) as a result of combined coronal hole fast wind and ongoing and forecast CME influence.” The South African National Space Agency (SANSA), has also issued a similar forecast, “Slight enhancements in solar wind speed are expected tonight into tomorrow (28 October) due to the expected CME arrival. Geomagnetic conditions are expected to be at quiet to unsettled levels (Kp 1-3), with a chance of active to G1/Minor storm intervals (Kp 4-5).”
